1. Field of the Invention
This invention relates to an uplift spring assembly for the main bearing of a mooring turret to compensate for the hull deflection or distortion of the moored vessel.
2. Description of the Prior Art
Heretofore, springs have been provided for supporting the upper bearing of a mooring turret for a moored vessel. The mooring turret is usually mounted for rotation within a moon pool in the body or hull of the vessel. The vessel weathervanes about the turret which is anchored to the sea floor.
U.S. Pat. No. 5,306,186 dated Apr. 26, 1994 illustrates a mooring system including a turret supported within a moon pool on a main upper bearing mounted on the hull of the moored vessel. An upper turret support ring on the body of the vessel has a plurality of elastomeric pads equally spaced about the outer periphery of the turret for absorbing vertical shocks between the turret and the vessel. The elastomeric pads function to minimize moment load imbalances between the turret and vessel and to compensate for manufacturing tolerances of the upper bearing supports. The elastomeric pads are placed in compression upon downward movement of the turret relative to the body of the vessel.
3. Identification of Object of the Invention
A principal object of the invention is to provide an elastomeric spring assembly for the upper bearing of a mooring turret which includes a first elastomeric spring which is placed in compression upon an upward movement or uplifting of the turret relative to the vessel and a second elastomeric spring which is placed in compression upon a downward movement of the turret relative to the vessel.
The object identified above as well as other objects and features of the invention are provided in a spring assembly for the upper main bearing between a mooring turret and a vessel. An elastomeric spring is provided to react against turret uplift loads and downlift loads. A load applying horizontal ring connected to the main upper bearing has upper and lower elastomeric pads positioned on opposed sides thereof. A tie-rod extends through the load applying ring and the opposed elastomeric pads. The tie-rod is anchored at its lower end to a base support on the vessel. The upper end of the tie-rod is anchored an upper retaining plate. Upon an upward or uplifting movement of the turret, the tie-rod is effective to prevent movement of the retaining plate for transmitting a compressive force against the upper elastomeric pad thereof to permit the absorbing of the uplifting force by compression of the upper elastomeric pad. The lower elastomeric pad is compressed against the base support on the vessel by the load applying ring and is effective to absorb a downward force from the turret and load applying ring.